Cylindrical broom



Feb. 9, 1965 ga. MQBAQK 3,168,756

(CYLIJNDRC'L BRQM @im March 2 1954 l. j INVENTOR BENJAMIN KOBACK United States Patent O 3,168,756 CYLINDRICAL BROGM Benjamin Kohack, Portland, Oreg., assigner to Ben-Ko- Matic, Inc., Portland, Greg., a corporation of regon Filed Mar. 2, 1964, Ser. No. 348,678 4 Claims. (Cl. 15-182) This invention relates to improvements in a cylindrical broom or brush.

In this type of brooms and brushes it is common practice to clamp return bend mid portions of the bristles in a helical groove in a core member by a binding rope, causing the ends of the bristles to stand out radially from the core member. Heretofore the helical groove has been smooth and, when the bristles are also smooth, Some diculty has` been experienced from the tendency of the'bristles to shift along the groove whereby there would not be a uniform distribution of the bristles. It is obviously desirable to have the bristles distributed uniformly and also to lock them securely in place without the use of adhesive.

It is, therefore, the general object of the present invention to provide improvements in cylindrical broom and brush construction of the type described which will assist in the uniform distribution of the bristles when the bristles are applied to the core and which will also positively lock the bristles in position so that they cannot be displaced. More particular objects are to provide Van improved form of core construction which will prevent movements of the bristles along the groove, to provide a groove shape which will gather the bristles into tufts which must remain separate from each other at theirclamping points in the bottom of the groove, and to provide a simple and effective manner of forming hollows and ridges in the groove which will not materially increase the cost of construction of the broom.

In the present construction the helical groove is preferably formed by a metal channel member which is wrapped around and fastened to an inner part of the core member. In the bending of the metal channel it is caused to wrinkle transversely on the inside of the bend forming a succession of ridges extending transversely across the bottom of the groove. Between successive ridges there are pockets or hollows to receive tufts of the bristles and, as the binding rope is applied, each tuft of bristles is securely locked in its own pocket so that it cannot shift along the groove. The invention will be better understood and additional objects and advantages will become apparent from the following description of the preferred embodiment of the invention illustrated on the accompanying drawing. Various changes may be made, however, in the details of construction and all such modifications within the scope of the appended claims are included in the invention.

In the drawing:

FIGURE l is a perspective View showing a cylindrical broom embodying the principles of the invention, one end of the core being exposed to view without bristles;

FIGURE 2 is a cross sectional view taken on the line 2-2 of FIGURE 1;

FIGURE 3 is an enlarged fragmentary perspective View showing the manner in which the bristles are secured in the groove by the binding rope;

FIGURE 4 is a cross sectional View taken on the line 4 4 of FIGURE 3; and

FIGURE 5 is a longitudinal sectional View taken on the line 5-5 of FIGURE 4.

The invention is applicable to various types of cylindrical brooms and brushes but for the purpose of illustration there is shown in FIGURE l a typical rotary lhh Patented Feb. 9, i965 ICE broom of the type used in street sweeping machines and the like. In this typical form of construction the broom core comprises an inner metal tube It) which is adapted to he mounted for rotation. The outer surface of the tube l() carries a plurality of longitudinal i members 11 which support a helical metal channel member 12. The three parts lil, 1I and 12 are rigidly connected together to form an integral unit which constitutes the core member. The groove 13 of channel l2 receives the return bend mid portions of bristles ILS which are clamped tightly in the groove by means of binding rope 16. This general arrangement is conventional.

In some cases the bristles may be fed by hand as the binding rope is trained around the groove but it is more common practice to assemble the bristles` on the core by an automatic machine which feeds the bristles to the core in such a way that they will be distributed and clamped in the manner described. In any case, the binding rope is applied to the groove by securing one end to the core and then rotating the core while maintainingtension on the rope. The bristles are fed into the nip between the rope and the groove so as to become clamped in the groove by the rope tension. Channel member 12, it will be noted, is shown in the drawings as having a rounded base (whereby the base of groove f3 is also rounded), curved so as to complement the curvature of the circumference of the rope used in clamping the bristles, whereby the return bend mid portions of the bristles are clamped tightly in that region where they become lodged between the rope and the channel member over a substantial range of their length.

The binding rope may be either liber or metal cable and the bristles may be either natural fibrous material, synthetic material or metal. When the bristles are of a material which has a smooth surface, they tend to slide out of position in regular orderly distribution along the groove whether they are fed by hand or by machine whereby there is a tendency for the bristles to bunch up irregularly when they can shift freely along the groove. The present improved form of construction provides a remedy for this undesirable condition.

In the present construction the bottom of channel 12 is caused to wrinkle as it is bent around the core tube 1t) producing transverse ridges 20 in the bottom of the groove at regular intervals, leaving hollows or pockets 21 between the ridges. Then, as the bristles 15 are applied between the rope 16 and the groove 13, the ridges 2t) separate the bristles into tufts which become clamped in fixed positions in the hollows 21. Each hollow 21 forms a pocket for one tuft which is walled in against slippage longitudinally of the groove by the ridges 20. Regardless of the smoothness of the bristles, they cannot slide from one pocket to another. Preferably, the pockets are of sucient depth to contain the desired amount of bristles when they are compressed by the rope, whereby the rope makes contact with the ridges Ztl but the ridges will serve the purpose even when they are of less height.

Preferably, also, the ridges 2l) are limited to the rounded bottom portion of the groove 13 and do not extend up the flat sides of the channel on either side of the base of the channel. This permits the bristles to ilex in a gradual bend over a greater length when the broom is rotated in contact with the street surface with the bend extending back to the point of substantial clamping pressure between the rope and the chaunel which is around the base of the rope and the region where the rounded base of the channel complements the rope. Near the rim of the channel the bristles are not clamped between two members, but only rest against the llat sides of the channel on either side of the curved channel base, and can move to accommodate a degree of bending in this region during the sweeping action whereby excessive bending does not tend to concentrate at a definite point of positive mechanical restraint. In other words, a degree of sliding along the wall of the groove is permitted along the outer edge of the wall but is positively prevented in the bottom of the groove. This provides improved fiexibility for the bristles and results in longer life of the brush.

It should be noted, as can be seen in FIGS. 4 and 5, that ridges 2@ extend transversely of the rounded base of the channel and have ends curving upwardly where the curved base extends to meet the flat channel sides on either side of the base. Progressing toward these ends, the height of a channel gradually diminishes, until the channel terminates at points Well upwardly on the curved base close to the starting point of the flat sides. When clamping the reverse bends of bristles in place under a rope, the-upwardly directed diminishing ends of the ridges function to produce proper positioning of clusters or tufts of bristles finally lodged in separate pockets defined by the ridges, by directing expanses of bristles adjacent their reverse bend portions in a proper transverse direction across the flat sides of the channels.

The invention is not necessarily limited to rotary, power-operated brooms but is of advantage in any cylindrical brush where the bristles are bound in a helical j groove by a binding cord. Although the bristles are separated into tufts, the adjacent tufts are so close together that the number of bristles is not substantially reduced for this reason and the action of the broom or brush is superior to the action of one where the bristles areintended to be distributed uniformly along the groove but where such ideal uniformity of distributton is not ordinarily attained or maintained in practice. The tufting of the bristles is not apparent in the finished brush as the outer ends are substantially uniformly distributed the same as in conventional brooms. It is not necessary to employ a channel member to provide a helical groove but this form of construction lendsV itself particularly well to the convenient formation of the desired ridges and pockets as described.

In order to provide additional frictional resistance against sliding of the bristles along the groove, the bottom of the curved groove is preferably roughened as by knurling as shown on the drawing. This forms additional smaller ridges extending across the bottom of the groove and increases the frictional contact between the curved base of the groove and the reverse bend portions of tne bristles. The knurling extends over the upwardly curving portions of the rounded base where tight contact is produced by a rope, but it is important to note that the knurling terminates before the fiat sides of the channel are reached, where the bristles only rest against the flat sides. These iiat sides are left smooth because, as previously explained, bristle movement takes place over these sides and roughening in these areas only serves to introduce wear.

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. A broom comprising a rope, a cylindrical core having a helical groove adapted to receive bristles, said groove having a rounded base complementing the curvature of the rope and flat sides joining with upper margins of said rounded base, transverse ridges in the base of said groove defining hollows between the ridges, said ridges extending upwardly into said upper margins of said base to adjacent the joinder of the sides of the groove with said base, and bristles in said groove, said rope also being lodged in said groove and clamping over a portion of the circumference thereof said bristles in said groove with the bristles distributed between said ridges and directed transversely of the channel sides by said ends of said ridges. Y

2. A cylindrical broom comprising a core having a helical channel member, a rope in said channel member, said channel member having a rounded base compleinenting the curvature of the circumference of the rope andk flat sides joining with upper margins of said rounded base, transverse wrinkles in the bottom of said channel member forming ridges across the bottom of the channel, said ridges extending upwardly into said upper margins of said base to adjacent the joinder of the channel sides with said base, pockets between said ridges, separate tufts of bristles in said pockets, said rope in said channel serving to clamp said tufts in said pockets with the bristles directed transversely of the channel sides by said ends of said ridges.

3. The broom of claim 2, wherein said fiat sideshave l smooth opposed inner faces, and the curved base of the channel is roughened relative to the sides over a region extending to adjacent the joinder of said curved base with said channel sides.

4. A cylindrical broom comprising a core having a helical channel member wrapped about the core and secured thereto, a rope lodged in said channel member extending along the length of the channel member, said channel member having a rounded base complementing the curvature of the circumference of the rope where the rope is lodged therein and fiat sides joining with upper margins of said rounded base, transverse ridges in the rounded base of said channel member defining pockets between the ridges, said ridges extending upwardly into said upper margins of said rounded base and gradually diminishing in size progressing upwardly to said fiat sides to terminate adjacent the joinder of the channel sides with said rounded base, bristles distributed in clusters in said pockets defined by said ridges and held by said rope in said channel member, said rope while lodged in the channel member clamping over a portion of its circumference thereof against said bristles with the bristles directed transversely of the channel sides by said ends of said ridges, said fiat sides of said channel member having smooth opposed inner faces and the rounded base of the channel member being roughened relative to the fiat sides over a region extending to adjacent the joinder of said rurved base with said channel sides to increase the frictional contact of the base of the channel member with portions of the bristles lodged under the rope, said flat sides by being relatively smooth accommodating transverse shifting of bristle portions that lie against the flat sides.

References Cited by the Examiner UNITED STATES PATENTS 549,106 11/95 Clements 15-182 2,288,337 6/42 Whittle 15-179 X 2,553,748 5/51 Carlson 15--182 FOREIGN PATENTS 526,851 6/31 Germany.

CHARLES A. WILLMUTH, Primary Examiner. 

1. A BROOM COMPRISING A ROPE, A CYLINDRICAL CORE HAVING A HELICAL GROOVE ADAPTED TO RECEIVE BRISTLES, SAID GROOVE HAVING A ROUNDED BASE COMPLEMENTING THE CURVATURE OF THE ROPE AND FLAT SIDES JOINING WITH UPPER MARGINS OF SAID ROUNDED BASE, TRANSVERSE RIDGES IN THE BASE OF SAID GROOVE DEFINING HOLLOWS BETWEEN THE RIDGES, SAID RIDGES EXTENDING UPWARDLY INTO SAID UPPER MARGINS OF SAID BASE TO ADJACENT THE JOINDER OF THE SIDES OF THE GROOVE WITH SAID BASE, AND BRISTLES IN SAID GROOVE, SAID ROPE ALSO BEING LODGED IN SAID GROOVE AND CLAMPING OVER A PORTION OF THE CIRCUMFERENCE THEREOF SAID BRISTLES IN SAID GROOVE WITH THE BRISTLES DISTRIBUTED BETWEEN SAID RIDGES AND DIRECTED TRANSVERSELY OF THE CHANNEL SIDES BY SAID ENDS OF SAID RIDGES. 